Gun perforator for wells



Sept. 14, 1954 F. A. BEYER, JR.. ET AL GUN PERFORATOR FOR WELLS FiledApril 25, 1952 FIG. 4.

Frank A. Beyer Jr.,

FIG. 2.

INVENTORS.

By Bliss Adamson,

ATTORNEY- Patented Sept. 14, 1954 STATS PATENT OFFICE UN PEB LE B F WELLFrank A. Beyer, Jr., and Bliss Adamson, Duncan,

Okla, assignors to Halliburton Oil Well Cementi g flamrau an 9km-Application April 25, 195.2, Serial No. 284,418

3 laims- 1 This invention relates to gun perforators for use in oilwells or the like and more particularly to an arrangement for properlylocating guns in the casing of a well which is to be perforated so as tocause the guns to have efficient operation.

It is common practice to perforate casing in a bore hole, such as an oilwell, by the use of bullet guns or shaped charges of explosive. Animportant factor in th efficiency of such guns is the amount ofstand-01f or distance from the gun to the casing.

In many gun designs this distance has not been accurately controlled.The carriage for the guns must be considerably smaller in diameter thanthe inside diameter of the casing to avoid the danger of hanging thetool in the well and this means that ordinarily, the assembly is layingalong one side of the bore hole when the guns are being fired.

It has been proposed heretofore to mount all the guns in the carriagefacing the same direction and p ace o e or more d ase rinss 9 th 0ppo tesidehen a l the sun have the pr per stand-01f.

However, it is best to stagger the direction of fire to some extent sothat if the cement around the casing has channelled somewhat, or isthickor along one side of the casing than the other, effectiveperforation into a producing formation can still be accomplished.

In accordance with the present invention, a novel drag-springarrangement is provided which causes the gun carriage to be held firstin the proper stand-01f position for one set of the guns and then inanother position to bringabout the proper stand-01f position for anotherset of guns facing in a different direction. The arrangement is suchthat after the first set of guns are fired, the carriage automaticallyshifts to another position, the movement being controlled by the firingof the last gun of the first set.

Referring to the drawing, which shows a mechanism for bringing aboutthis result:

Fig. 1 is a side view of a gun assembly constructed in accordance withthe present invention located in a well bore, the casing of which isshown in cross-section.

Fig. 2 is a vertical cross-sectional view of the lower portion of theassembly of Fig. 1 and show- Fig. 4 is a diagrammatic view of the gunassembly showing one way of making the electrical connections to theguns to cause them to fire in the desired sequence with relation to theposition of the drag-springs.

Referring to the drawing in detail, it will be seen from Fig. 1, that agun carriage I! is lowered into the casing l2 of a well on an electricalcable l3. The gun carriage is provided w th a number of guns. Forconvenience, ten guns, numbered I to ill have been shown, and these havebeen illustrated as employing bullets to do the perforating, although itwill be readily understood that the invention is of application to jetperforation or any otherperforators where stand-off is a factor in theiroperation.

As illustrated in the drawing, the guns are alternatel arranged to facein the opposite 'directions. Thus guns numbered 1, 3, 5, l and 9 areshown facing the left and guns 2, l, 6, 3 and III are shown facing theright.

The lower gun Ill of the assembly is construct.-

ed the same as the others except that it is preferably mounted inadetachable section M of the assembly and is adapted to control theposition of the drag-springs.

As shown in Fig. 3, there is a screw-threaded joint 15 between thesection M and the main portion H of the assembly. This joint l5 has anelectrical coupling l6 therein for making connection for the gun It].This coupling [6 may be of the type ordinarily used for makingconnections between sections of the gun assembly, which, as commonlyemployed may consist of the number of sections required to make as manyshots as desired, with one trip in the hole.

As illustrated, two drag-springs designated l1 and [3 are employed. Bothof these are mounted in the section M of the assembly beneath the gun IB. As the assembly is lowered into the hole, the drag-springs occupy theposition shown, with the spring I! exerting a greater influence on thecarriage than the drag-spring l8 so that the carriage rides along, butspaced from, the left-hand side of the casing, as shown in Fig. 1. Whenthe gun It fires, the drag-springs snap to a difierent position so thatthe drag-spring l8 exerts the greater influence and the carriage movesto the right.

The snap action mechanism for controlling the drag-springs is shown indetail in Fig. 2. The lower ends of the drag-springs l1 and I 8 arefreely ulidable in guide pins 20 while the upper ends are connected to apin 2| on an offset link 22 pivoted to the section I4 at 23. A coiltension spring 24 is connected between one of the guide pins 2!] and aconnection 25 on the link 22, which tends to swing the link 22downwardly and mo the pin 2| to the left at all times.

Movement of the link 22 from the position shown in Fig. 2 is preventedunti1 the gun I fires. The link 22 is connected by a shear strap 26 tothe section M, the strap extending across the muzzle of the gun In asillustrated. When the gun l0 fires, the strap 26 breaks and thedrag-springs move with respect to the carriage.

The section I4 is hollow and provided with slots 21 to accommodate thedrag-springs i1 and I8 and it may be provided with a suitable nose 28.

With the arrangement illustrated the gunlll' will not be a eifective asthe others in perforating the casing. In the first place it will expendsome energy in bursting the strap 26. Secondly it will not have thecorrect stand-off.

The arrangement could be so arranged that the gun l0 faced in the samedirection as the gun 9 and hence have the proper stand-off, but thiswould complicate the structure of the strap 26 and the structure shownis preferred because of its simplicity.

Any desired electrical system may be used for firing the guns in thedesired sequence. The details of the electrical system are not shown ordescribed herein since they are well known. The U. S. patent to RobidouxNo. 2,338,872 granted January 11, 1944, shows a suitable system.

It is to be noted, however, that the gun I!) should fire in between thetwo sets of guns which fac in opposite directions. One way ofaccomplishing this is to provide two step-by-step switches similar tothose shown in the Robidoux patent cited. This is illustrated in Fig. 4.

A suitable firing order for the guns is i, 3, 5, 1, 9, l0, 8, 6, 4, 2.The odd-numbered guns are then fired when the drag-spring I! is exertingthe greatest influence and the even-numbered guns except gun 10, arefired when the dragspring I8 is exerting the greatest influence on theposition of'the carriage.

The switching arrangement illustrated in Fig. 4 is such as to bringabout the above firing order. The conductor 29 of the cable I3 isconnected to a step-by-step switch 30, the buttons of which areconnected to guns I, 3, 5, l and 9. In addition this switch 30 has abutton 32 connected to the moving arm of a second step-by-step switch 3|the buttons of which are connected respectively to the guns l0, 8, 6, 4and 2. The switch 30 is actuated first. When its arm is moved to contactbutton 32 it stops and the signals from the conductor then travel to theswitch 3|. Of course, any other switching mechanism may be provided, oneway being merely to rearrange the connections in a system like that ofthe Robidoux patent mentioned to cause the proper firing sequence. Ofcourse, the firing sequence in any given set need not be as given. It isimportant only that the guns facing one direction all be fired beforethose facingin the other direction are fired.

While only on embodiment is shown and described herein, it is obviousthat various changes may be made without departing from the spirit ofthe invention or the scope of the annexed claims.

We claim:

1. A gun perforator for use in a well bore, comprising, in combination,a carriage, a, plurality of guns mounted in the carriage, one set ofwhich is facing in one direction and another set of which is facing inanother direction, means for holding said carriage alternately inproximity to one wall or another of the Well bore corresponding to thedirections of said sets of guns, said means including a pair ofdrag-springs mounted on the carriage for controlling the stand-offposition of said sets of guns, linkage mechanism associated with saiddrag-springs for causing them to snap from one position to the otherandmeans for automatically controlling said linkage mechanism to causethe carriage to move after one set of guns has fired.

2. The combination of claim 1 in which a shear strap is mounted acrossthe muzzle of one of said guns and which holds the linkag mechanism inone position until that gun is fired.

3. The combination of claim 1 in which the automatic means includes astrap and an explosive charge capable of bursting the strap.

Name Date Spencer Mar. 9, 1943 Number

